Fig. 4
The progressive increase in mortality with time following the pyrethroid-resistance augmenting effects of heat shock in insecticide-resistant Anopheles arabiensis. Deltamethrin-induced mortality decreased after a short-term heat shock (37 °C for 3 h; 39 °C for 1 h, both with a 1-h recovery period) (A), as did λ-cyhalothrin induced mortality (B). Deltamethrin-induced mortality returned to pre-heat shock levels 7 h after the initial heat shock for the 39 °C heat shock but not the 37 °C heat shock treatment. The effects of the 37 °C heat shock decreased in a linear fashion (r2 = 0.95), while the linear decrease following exposure to the 39 °C heat shock was less pronounced (r2 = 0.63). There was no significant difference in the effect of 37 and 39 °C heat shock on λ-cyhalothrin resistance, and both showed a linear decrease in the expression of heat shock-induced resistance